Objects that are shipped or stored in containers may be damaged by stress applied externally to the container. Such externally applied stress may take the form of one or more of rough handling, dropping, and bumping the container. Externally applied stress also may take the form of thermal cycles in which the container is subjected to extended periods of temperatures sufficiently high to damage the objects in the container or package. Damaging thermal cycles also may take the form of localized heating of less than the entire container to a temperature and for a time sufficient to damage the objects within.
Objects such as sensitive electronic instruments may be vulnerable to external stresses resulting from such rough handling, dropping and bumping, and also sensitive to exposure to high temperatures. Sensitive objects may include items such as chemicals, paints, biological substances, and live animals such as fish. These objects must be maintained within a relatively narrow temperature range when transported, and also may be susceptible to damage resulting from impacts to the containers in which they are shipped.
Such objects may arrive damaged to the recipient, but the exposure of the shipped or stored objects to damaging impacts, or to extended high temperatures during transportation or storage of the object, may not be readily apparent from an inspection of the object or the container. Consequently, it may difficult to prove that damage to the object within the container was sustained during the transportation of the object in the container, as opposed to the object being shipped in an original, damaged condition. It is therefore difficult in such circumstances to file a claim with a transporter of the object because there is no evidence that the damaging impact or damaging high temperature occurred during shipment.
Accordingly, there is a need for a non-destructive inspection technique that may readily and inexpensively indicate whether an object is subjected to stresses in the nature of impacts and/or damaging high temperatures during shipment.